JP2797393B2 - Recording and playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus, and more specifically, to a recording / reproducing apparatus having a solid-state imaging device in which pixel arrangement is offset.

[Prior art] Conventionally, a recording / reproducing apparatus using a solid-state imaging device has been
It is widely known as the S system, 8 mm video system, electronic still camera, and the like. As solid-state imaging devices used for these, those having a photosensitive portion in which square or rectangular light-receiving elements are regularly arranged in a matrix were used. High image quality is achieved, and as a result, as shown in FIG.
A solid-state imaging device has been developed in which each pixel (light-receiving element) has a rhombic or hexagonal shape, and the center of gravity of each pixel has an offset-sub-Nyquist sampling structure. With this pixel arrangement, it is possible to improve image quality while suppressing a reduction in light receiving area (that is, a decrease in sensitivity).

However, in the imaging device shown in FIG. 2, as shown by an arrow (solid line or broken line) in FIG. 2, when a signal is read zigzag on a horizontal line to form a TV signal, moire is generated. It is necessary to interpolate the signal of the part (for example, the point of □ when ○ is a sample point)
Further, in order to limit the band in the horizontal direction, it is necessary to provide a two-dimensional filter having a huge signal processing unit. For the interpolation processing, a frame memory for temporarily storing the output of the image sensor as an offset sub-Nyquist sample is provided.

[Problem to be Solved by the Invention] In the above conventional example, a frame memory for temporarily storing the output of the image sensor as an offset sub-Nyquist sample is provided for interpolation processing of an offset signal. In general, a reproducing apparatus is provided with a frame memory for temporarily storing a reproduced signal in order to perform a predetermined process on a reproduced signal from a recording medium or to perform a special reproduction. flame·
It is preferable to use the memory also. However, when a reproduced signal is stored, a signal obtained by normal sampling is stored. Therefore, if an attempt is made to have the same horizontal resolution, a larger memory capacity is required at the time of reproduction than at the time of imaging.

In order to reduce the memory capacity at the time of reproduction to the same extent as at the time of imaging, it is only necessary to store a signal by offset / sub-Nyquist sampling at the time of reproduction. Requires two-dimensional filter processing, and the circuit scale becomes huge.

Therefore, an object of the present invention is to provide a recording and reproducing device that solves such a problem.

[Means for Solving the Problems] A recording / reproducing apparatus according to the present invention includes: an imaging element in which a photoelectric conversion element of a photosensitive unit has a two-dimensionally offset structure;
A frame memory for storing an image signal from the image sensor, a filter for forming an interpolation signal by interpolating an output signal of the frame memory, a recording unit for recording an interpolation signal formed by the filter, Reproducing means for reproducing the interpolation signal recorded in the means, offset / subsampling means for offset / subsampling the interpolated signal reproduced from the reproducing means, and inputting the output of the offset / subsampling means to the frame memory And a reproduction luminance signal forming means for forming a reproduction luminance signal via the filter.

[Operation] With the above-described means, the frame memory can be used also for reproduction with a small capacity corresponding to the memory capacity for recording.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration block diagram of one embodiment of the present invention.
Reference numeral 10 denotes an image sensor having a light receiving element array of the photosensitive section having an offset / sub-Nyquist sample structure as shown in FIG. 2, and outputs three color signals of R, G, and B. Reference numeral 12 denotes a switch for sequentially selecting three outputs of the image sensor 10 (for example, in the order of arrows in FIG. 2) to form a signal corresponding to a luminance signal. Reference numeral 14 denotes a sample / hold (S / H) circuit; Is a selection switch, 18 is an A / D converter that has both white balance and gamma correction functions, 20 is a frame memory, 22 is a switch for separating luminance and chrominance signals during playback, and 24 and 26 are vertical LPFs (Low pass filter), 28 is horizontal LPF for luminance signal, 30 is horizontal L for chrominance signal
PF, 32 is a switch for rearranging RGB signals, 34 is RGB
It is a matrix circuit.

36 is a signal passing through the vertical LPF 24 and the horizontal LPF 30 and
Switching circuit for switching between signals passing through LPF 26, 38, 40, 4
2 is a D / A converter, 44, 46, 48 are LPFs for removing harmonics by the D / A converters 38, 40, 42, 50 is an input signal recorded on a recording medium, and 50 is a recording signal of the recording medium. Recording and playback device for playing back
Reference numeral 52 denotes an encoder that forms a luminance signal and a chroma signal of a predetermined format from the outputs of the LPFs 44, 46, and 48. Reference numerals 54, 56, and 58 denote LPFs that limit the output (reproduction signal) of the recording / reproduction device 50.
A switch for forming a signal of inter-field offset sampling from each output of 58. 62 is a synchronizing signal generation circuit (SSG), and 64 is a system control circuit that controls the entire system.

First, the operation at the time of shooting and recording will be described. In this case, the switch 16 is connected to the contact b side, and the output of the image sensor 10 is applied to the frame memory 20 via the switch 12, the S / H circuit 14, the switch 16 and the A / D converter 18, It is memorized. The switch 22 is connected to the a contact side during photographing, and the stored signal of the frame memory 20 passes through the vertical LPF 24, becomes a luminance signal by the horizontal LPF 28, and is output by the horizontal LPF 30, the RGB switch 32 and the RG.
The B matrix circuit 34 generates the color difference signals RY and BY.
The switching circuit 36 is connected to the output side of the RGB matrix circuit 34. A luminance signal is obtained by the D / A converter 38, and the D / A converter
From 40 and 42, color signal signals are obtained. LPF44,46,48 removes harmonics from D / A converter 38,40,42 output
The signals are applied to the Y, RY, and BY inputs of 50, and the recording / reproducing apparatus 50 records the data on a recording medium (not shown).

Next, the operation at the time of reproduction will be described. A / D by LPF54,56,58
The aliasing of the conversion is removed, and the luminance signal and the color difference signal are inter-field offset-sampled by the switch 60 as shown in FIG. During this operation, the switch 16 is connected to the contact a, and the output of the switch 60 is
16 to the A / D converter 18 and the frame memory 2
Stored temporarily at 0. From the frame memory 20, the first
In the field, luminance, chrominance, luminance, chrominance, and so on are read in the order of the solid arrows in FIG. 3, and in the second field, they are read in the order of the dashed arrows in FIG. The signal read from the frame memory 20 is decomposed into a luminance signal and a chrominance signal by the switch 22, and the signals are separated into vertical LPFs 24 and 26, respectively.
It is distributed to. That is, the luminance signal passes through the vertical LPF 24 and the horizontal LPF 28, is converted into an analog signal by the D / A converter 38, and the color difference signal passes through the vertical LPF 26 and the switching circuit 36, and the D / A
The signals are converted into analog signals by the converters 40 and 42. LPF44,46,48 is D /
The harmonics due to the A conversion are removed, and the encoder 52 uses LPFs 44 and 4
The luminance signal Y and the chroma signal C of the predetermined system are obtained from the outputs of 6,48.
To form

In the above embodiment, the recording / reproducing apparatus in which the color difference signals have the same order is taken as an example. However, it goes without saying that the same applies to the case where the color difference signals are line sequential. In addition, when a recording medium in which the sampling signal of the pixels of the photosensitive section is photographed by an image sensor having a square lattice and a photographing signal is recorded in a state in which the spectrum in the oblique direction is not dropped is loaded into the recording / reproducing apparatus 50 and reproduced, a slight Aliasing occurs, but in many cases, the aliasing is weakened and is less noticeable due to deterioration of frequency characteristics due to the imaging system and the recording / reproducing system and characteristics of the front optical LPF.

FIG. 4 is a block diagram showing the configuration of another embodiment of the present invention. However, for the sake of simplicity, only the luminance signal processing portion is shown. Further, although a 3 × 6 filter is used as the two-dimensional filter, the present invention is not limited to this.

At the time of photographing and recording, the switches 74, 78, 84 and 90 are connected to the b contact, and the switches 76 and 92 are connected to the a contact. Reference numeral 70 denotes an image sensor having a photosensitive portion having an offset / sub-Nyquist sampling structure, similarly to the image sensor 10 of FIG. 1, and its signal is zigzag by a switch 72 as shown by an arrow in FIG. Is read. The output of the switch 72 is sampled and held by the S / H circuit 73, gamma-corrected (or white-balanced when a color signal is also processed) by the A / D converter 75, and stored in the frame memory 79. Memory 79
The signal read from the
The signal is separated into signals for each field by 80, and is twice oversampled by switches 81 and 82, respectively (5th
(FIG. 9B), input to the line memories 83 and 85. Thereafter, the two-dimensional filters are equivalently applied by the vertical LPFs 86 and 87 and the horizontal LPF 91, converted into an analog signal by the D / A converter 95, applied to the recording / reproducing device 97 through the LPF 96, and recorded on a recording medium.

At the time of reproduction, the switches 74, 76 and 77 are connected to the contact a, and only the first field is oversampled twice and stored in the frame memory 79. FIG. 6A shows the pixel arrangement of the first field in the memory 79. Next, by connecting the switches 76, 77, 90 and 92 to the b contacts and the switches 80, 81 and 84 to the a contacts and switching the switch 78, as shown in FIG. A second field interlaced scanning line is formed and the signal
Apply an equivalent two-dimensional filter with 8 and the horizontal LPF91.
FIG. 6C shows the pixel arrangement after the two-dimensional filter processing. The signal indicated by the mark x in FIG. 6C is taken out by the switch 92, written into the frame memory 79 again, and the data of the sub-Nyquist sample is stored in the memory 79.

When converting to a television signal, it is sufficient to read out from the memory 79 and interpolate with a two-dimensional filter, as in the case of a shooting signal.

In the present embodiment, even during playback freeze, two-dimensional filtering for offset / sub-Nyquist sampling is performed, and signals recorded without sub-Nyquist sampling by another device are also subjected to area Almost no image degradation due to jittering appears. Further, the memory 79 needs only to have a memory capacity for sub-Nyquist sampling, and can be downsized.

[Effects of the Invention] As can be easily understood from the above description, according to the present invention, the capacity of the memory for temporarily storing image signals can be reduced, and the use efficiency can be reduced by sharing the two-dimensional filter. To prevent the circuit size from increasing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a pixel arrangement of a photosensitive portion of an image sensor, FIG. 3 is an explanatory diagram of a reading order of the image sensor 10 of FIG. 4 is a block diagram of another embodiment of the present invention, FIG. 5 is an explanatory diagram of signal processing at the time of photographing and recording of FIG. 4, and FIG. 6 is an explanatory diagram of signal processing at the time of reproduction of FIG. 10, 70: Image sensor, 20, 79: Frame memory, 24, 26, 86, 8
7,88: vertical LPF, 28, 30, 91: horizontal LPF, 50, 97: recording / reproducing device

Claims (1)

(57) [Claims] An image pickup device in which a photoelectric conversion element of a photosensitive section has a two-dimensional offset structure, a frame memory for storing an image pickup signal from the image pickup device, and an output signal of the frame memory interpolated. A filter for forming an interpolation signal by the filter, a recording unit for recording the interpolation signal formed by the filter, a reproduction unit for reproducing the interpolation signal recorded on the recording unit, and an interpolation signal reproduced from the reproduction unit. Offset / subsampling means for performing offset / subsampling, and reproduction luminance signal forming means for inputting an output of the offset / subsampling means to the frame memory and forming a reproduction luminance signal via the filter. Characteristic recording / reproducing device.